Biotech letter gets notice online, but is it true?

DES MOINES, Iowa 
A letter by a retired Purdue University professor who says he has linked genetically modified corn and soybeans to crop diseases and health problems in livestock is being met with skepticism among other scientists.

They say the claims hasn't been properly verified because professor emeritus Don Huber won't provide evidence to back them up.

Huber sent the letter to U.S. Agriculture Secretary Tom Vilsack in January, saying a new organism has been discovered in corn and soybeans modified to resist the weed killer Roundup. Huber says he thinks the issue needs the USDA's immediate attention.

Purdue says the research was not done there.

The USDA acknowledged receiving the letter, but it does not appear the agency is investigating.